The present invention relates to a damper disc suitable for large and heavy-duty friction clutch discs.
In a known type of damper disc, a pair of side plates are arranged at both sides of a flange of a hub splined to an output shaft. The side plates and the flange are connected through torsion springs fitted in openings in the side plates and the flange.
However in this known type of the damper disc, considering that the strength of the flange and the side plates is reduced by said openings, at most six (or six pairs of) torsion springs can be employed, and it is difficult to employ more than six springs. Therefore total rigidity of the whole torsion springs can not be set sufficiently large, and the torsion springs can not effectively absorb strong torque vibration. In such case that hard torsion springs are employed for absorbing the strong torque vibration, the springs strongly engage and press side edges of the openings. Therefore, the side edges of the openings and the torsion springs wear severly, resulting in low durability.
Accordingly, it is an object of the invention to provide an improved damper disc, wherein a spline hub has at least two flanges, each of which has openings for torsion springs, so that the number of the torsion springs increases.
Other and further objects, features and advantages of the invention will appear more fully from the following description of the preferred embodiments of the invention.